| From e7d445ab26db833d6640d4c9a08bee176777cc82 Mon Sep 17 00:00:00 2001 |
| From: Tom Lendacky <thomas.lendacky@amd.com> |
| Date: Fri, 15 Oct 2021 12:24:16 -0500 |
| Subject: x86/sme: Use #define USE_EARLY_PGTABLE_L5 in mem_encrypt_identity.c |
| |
| From: Tom Lendacky <thomas.lendacky@amd.com> |
| |
| commit e7d445ab26db833d6640d4c9a08bee176777cc82 upstream. |
| |
| When runtime support for converting between 4-level and 5-level pagetables |
| was added to the kernel, the SME code that built pagetables was updated |
| to use the pagetable functions, e.g. p4d_offset(), etc., in order to |
| simplify the code. However, the use of the pagetable functions in early |
| boot code requires the use of the USE_EARLY_PGTABLE_L5 #define in order to |
| ensure that the proper definition of pgtable_l5_enabled() is used. |
| |
| Without the #define, pgtable_l5_enabled() is #defined as |
| cpu_feature_enabled(X86_FEATURE_LA57). In early boot, the CPU features |
| have not yet been discovered and populated, so pgtable_l5_enabled() will |
| return false even when 5-level paging is enabled. This causes the SME code |
| to always build 4-level pagetables to perform the in-place encryption. |
| If 5-level paging is enabled, switching to the SME pagetables results in |
| a page-fault that kills the boot. |
| |
| Adding the #define results in pgtable_l5_enabled() using the |
| __pgtable_l5_enabled variable set in early boot and the SME code building |
| pagetables for the proper paging level. |
| |
| Fixes: aad983913d77 ("x86/mm/encrypt: Simplify sme_populate_pgd() and sme_populate_pgd_large()") |
| Signed-off-by: Tom Lendacky <thomas.lendacky@amd.com> |
| Signed-off-by: Borislav Petkov <bp@suse.de> |
| Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> |
| Cc: <stable@vger.kernel.org> # 4.18.x |
| Link: https://lkml.kernel.org/r/2cb8329655f5c753905812d951e212022a480475.1634318656.git.thomas.lendacky@amd.com |
| Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> |
| --- |
| arch/x86/mm/mem_encrypt_identity.c | 9 +++++++++ |
| 1 file changed, 9 insertions(+) |
| |
| --- a/arch/x86/mm/mem_encrypt_identity.c |
| +++ b/arch/x86/mm/mem_encrypt_identity.c |
| @@ -27,6 +27,15 @@ |
| #undef CONFIG_PARAVIRT_XXL |
| #undef CONFIG_PARAVIRT_SPINLOCKS |
| |
| +/* |
| + * This code runs before CPU feature bits are set. By default, the |
| + * pgtable_l5_enabled() function uses bit X86_FEATURE_LA57 to determine if |
| + * 5-level paging is active, so that won't work here. USE_EARLY_PGTABLE_L5 |
| + * is provided to handle this situation and, instead, use a variable that |
| + * has been set by the early boot code. |
| + */ |
| +#define USE_EARLY_PGTABLE_L5 |
| + |
| #include <linux/kernel.h> |
| #include <linux/mm.h> |
| #include <linux/mem_encrypt.h> |